Month: August 2016

Pierre-Simon Laplace

From Wikipedia, the free encyclopedia taken on August 26, 2016

Pierre-Simon Laplace

Pierre-Simon, marquis de Laplace (/ləˈplɑːs/; French: [pjɛʁ simɔ̃ laplas]; 23 March 1749 – 5 March 1827) was an influential French scholar whose work was important to the development of mathematics, statistics, physics, and astronomy. He summarized and extended the work of his predecessors in his five-volume Mécanique Céleste (Celestial Mechanics) (1799–1825). This work translated the geometric study of classical mechanics to one based on calculus, opening up a broader range of problems. In statistics, the Bayesian interpretation of probability was developed mainly by Laplace.

Jean Léonard Marie Poiseuille (French: [pwazœj]; 22 April 1797 – 26 December 1869) was a French physicist and physiologist.

Poiseuille was born in Paris, France and he died there on 26 December 1869.

Fluid flow

From 1815 to 1816 he studied at the École Polytechnique in Paris. He was trained in physics and mathematics. In 1828 he earned his D.Sc. degree with a dissertation entitled Recherches sur la force du coeur aortique. He was interested in the flow of human blood in narrow tubes.

William Harvey (1 April 1578 – 3 June 1657) was an English physician who made seminal contributions in anatomy and physiology. He was the first known to describe completely and in detail the systemic circulation and properties of blood being pumped to the brain and body by the heart, though earlier writers, such as Realdo Colombo, Miguel Servet (aka Michael Servetus, Michel de Villeneuve) in: Christianismi Restitutio, Paris, 1546, and Jacques Dubois, had provided precursors of the theory.[1][2] In 1973 the William Harvey Hospital was constructed in the town of Ashford, several miles from his birthplace of Folkestone.

FAMILY

William’s father, Thomas Harvey, was a jurat of Folkestone where he served the office of mayor in 1600. Records and personal descriptions delineate him as an overall calm, diligent, and intelligent man whose “sons… revered, consulted and implicitly trusted in him… (they) made their father the treasurer of their wealth when they acquired great estates…(He) kept, employed, and improved their gainings to their great advantage.”[3] Thomas Harvey’s portrait can still be seen in the central panel of a wall of the dining-room at Rolls Park, Chigwell, in Essex. William was the eldest of nine children, seven sons and two daughters, of Thomas and his wife Joan Halke. Notable family connections include Heneage Finch, 1st Earl of Nottingham, who married William’s niece Elizabeth Harvey, and the diplomat Sir Daniel Harvey.

BIOGRAPHY

Galileo Galilei (Italian pronunciation: [ɡaliˈlɛːo ɡaliˈlɛi]; 15 February 1564 – 8 January 1642) was an Italian astronomer, physicist, engineer, philosopher, and mathematician who played a major role in the scientific revolution of the seventeenth century. He has been called the “father of observational astronomy”, the “father of modern physics”, and the “father of science”. His contributions to observational astronomy include the telescopic confirmation of the phases of Venus, the discovery of the four largest satellites of Jupiter (named the Galilean moons in his honour), and the observation and analysis of sunspots. Galileo also worked in applied science and technology, inventing an improved military compass and other instruments.

Galileo’s championing of heliocentrism and Copernicanism was controversial during his lifetime, when most subscribed to either geocentrism or the Tychonic system. He met with opposition from astronomers, who doubted heliocentrism because of the absence of an observed stellar parallex. The matter was investigated by the Roman Inquisition in 1615, which concluded that heliocentrism was “foolish and absurd in philosophy, and formally heretical since it explicitly contradicts in many places the sense of Holy Scripture. Galileo later defended his views in Dialogue Concerning the Two Chief World Systems, which appeared to attack Pope Urban VIII and thus alienated him and the Jesuits, who had both supported Galileo up until this point.[8] He was tried by the Inquisition, found “vehemently suspect of heresy”, and forced to recant. He spent the rest of his life under house arrest. While under house arrest, he wrote one of his best-known works, Two New Sciences, in which he summarized work he had done some forty years earlier on the two sciences now called kinematics and strength of materials.

Early life and family

Galileo was born in Pisa (then part of the Duchy of Florence), Italy, in 1564, the first of six children of Vincenzo Galilei, a famous lutenist, composer, and music theorist, and Giulia Ammannati. Galileo became an accomplished lutenist himself and would have learned early from his father a scepticism for established authority, the value of well-measured or quantified experimentation, an appreciation for a periodic or musical measure of time or rhythm, as well as the results expected from a combination of mathematics and experiment.

Aelius Galenus or Claudius Galenus (/ɡəˈliːnəs/; Greek: Κλαύδιος Γαληνός; September 129 AD – c. 200/c. 216), often Anglicized as Galen and better known as Galen of Pergamon (/ˈɡeɪlən/), was a prominent Greek physician, surgeon and philosopher in the Roman empire.[3][4][5] Arguably the most accomplished of all medical researchers of antiquity, Galen influenced the development of various scientific disciplines, including anatomy, physiology, pathology, pharmacology, and neurology, as well as philosophy and logic.

The son of Aelius Nicon, a wealthy architect with scholarly interests, Galen received a comprehensive education that prepared him for a successful career as a physician and philosopher. Born in Pergamon (present-day Bergama, Turkey), Galen traveled extensively, exposing himself to a wide variety of medical theories and discoveries before settling in Rome, where he served prominent members of Roman society and eventually was given the position of personal physician to several emperors.

Galen’s understanding of anatomy and medicine was principally influenced by the then-current theory of humorism (also known as the four humors – black bile, yellow bile, blood, and phlegm), as advanced by ancient Greek physicians such as Hippocrates. His theories dominated and influenced Western medical science for more than 1,300 years. His anatomical reports, based mainly on dissection of monkeys, especially the Barbary macaque, and pigs, remained uncontested until 1543, when printed descriptions and illustrations of human dissections were published in the seminal work De humani corporis fabrica by Andreas Vesalius where Galen’s physiological theory was accommodated to these new observations. Galen’s theory of the physiology of the circulatory system endured until 1628, when William Harvey published his treatise entitled De motu cordis, in which he established that blood circulates, with the heart acting as a pump. Medical students continued to study Galen’s writings until well into the 19th century. Galen conducted many nerve ligation experiments that supported the theory, which is still accepted today, that the brain controls all the motions of the muscles by means of the cranial and peripheral nervous systems.